They were identified as Rajendra Netam (39), Phooldas Markam (30) and Pawan Kumar Yadav (20).
The trio had allegedly demanded Rs 20 lakh from PWD Executive Engineer Devlal Singh Tekam, said Additional Superintendent of Police Surjit Atri.
The unidentified caller who threatened Tekam said he was a leader of Keshkal Dalam of the Maoists.
Police laid a trap after Rajendra, who masterminded the plan, asked Tekam to bring the money to a spot in the forest near Bahigaon village, and arrested the trio, the ASP said.
